Receipt counts your AI prompts — never what you type — and tells you what they cost, honestly.
You have probably been told two things about AI and energy: that one prompt boils a lake, and that it's nothing, stop worrying. Both are being said by people with something to sell.
Receipt doesn't settle that argument for you. It gives you your own number, as a range, with every factor sourced and graded — and it's blunt about the much larger part that isn't yours to optimise.
The useful finding is usually not the total. It's that a small handful of prompts on "thinking" modes account for most of the energy, and most of them were drafting jobs a standard model does identically. That's waste. Fixing it costs nothing and improves nothing about your output except the speed.
There is no server. The extension makes no network requests of any kind — not analytics, not error reporting, not a font. Everything sits in your browser's local storage until you delete it.
Don't take my word for it. In the extension folder:
grep -rE "fetch\(|XMLHttpRequest|sendBeacon|WebSocket|https?://" *.js
That returns nothing. There is no code capable of transmitting anything. Open DevTools → Network while using an AI site and you'll see Receipt generate no requests at all. The whole thing is around 200 lines and readable in ten minutes.
chrome://extensions (or edge://extensions).Chrome, Edge, Brave and Arc. Firefox needs a small change to the manifest; Safari needs Xcode packaging.
It will say Receipt can "read and change your data" on chatgpt.com, claude.ai and the other listed sites. That's Chrome's standard wording for any extension that runs on a page, and it can't be softened. It's accurate in that a content script could do those things. This one counts submissions and shows a nudge. That's the reason the source is short and the grep above is on this page.
Developer mode is disabled by policy in many organisations, and enabling it may be against your IT rules. Check before you install. This is an early build, unsigned and unreviewed — a signed Web Store version is coming.
Receipt is built for voluntary individual use. Please don't make it compulsory.
The moment you require staff to install it and send you their exports, you're processing employee data and the relevant framework is workplace monitoring — transparency, a lawful basis, and realistically a DPIA. More to the point, a tool designed so that nobody can watch you, deployed so that somebody does, becomes the opposite of the thing.
If you want an organisational picture, ask people to share their weekly totals voluntarily and only aggregate once enough have done so that nobody is identifiable. The export contains counts and energy ranges — never the reclaim log, never anything typed.
They're honest, which is not the same thing. Only one provider publishes a per-prompt energy figure with a proper method; another gave a number in a blog post; the rest publish nothing. So everything is a range, each factor is graded by evidence quality, and the method is one tap away in the extension. Water is weaker still — only the standard-prompt figure is provider-disclosed, and the rest is derived. It says so.
That's the right suspicion to have. It's why there's a permanent tab called "Not yours to optimise" — datacentre siting, water in already-stressed regions, the annotation workforce, the training footprint nobody discloses — and why the tool tells you your number is small rather than dressing it up. It also has a button for logging the times you did something without AI, because non-use is a valid outcome and every tool in this category pretends otherwise.
AI inside Office, Teams transcription, CRM suggestions, design tools, and anything on mobile. In a Microsoft shop that's a substantial share of real use. Thinking-mode detection relies on artefacts in the response and will break when vendors redesign — there's a manual override for when it gets it wrong.
Once a day at most, only when you switch into a thinking mode, and there's a permanent mute. No streaks, no badges, no score, no comparison with anyone else.
Receipt is an early, rough, independent build. It isn't selling you an AI product and never will.
Found something wrong? That's the most useful thing you can send me: marie@springcorp.co.uk